[EMBOSS] dottup and dotmatcher in 3.0.0

[F.J. Novo]

Hi all. There seems to be something wrong  with dottup and dotmatcher in 
3.0.0 (under Fedora Core 4). I consistently get an error:

[fnovo at localhost ~]$ dotmatcher
Displays a thresholded dotplot of two sequences
Input sequence: p53mRNA.seq
Second sequence: p53mRNA.seq
Graph type [x11]: png
Devices allowed are:-
postscript
ps
hpgl
hp7470
hp7580
meta
colourps
cps
tektronics
tekt
tek4107t
tek
none
null
text
data
png
Error: Invalid XY graph value 'x11'
Died: dotmatcher terminated: Bad value for '-xygraph' and no prompt

and the same for dottup.

Needless to say, png is properly installed and works fine with other 
applications (including dotpath and polydot), so it seems something 
specific to these two programs. Has anyone else seen this? Any suggestions?

Thanks,